How do you store a digital movie for 100 years?

Think about your favorite movie: Is it a classic, like Citizen Kane? Maybe it's something from the French New Wave, such as Jules and Jim. Or perhaps it's a contemporary blockbuster, like Avatar. Now imagine that movie just disappeared, and you could never watch it again on the big screen. · You don't need to worry about anything like that happening at the moment because the major movie studios go to great lengths to protect their treasures. They can do this efficiently and inexpensively for one reason: Photochemical film is cheap and easy to preserve. All you need is a cold room that's not too humid and not too dry, and the chemically processed film will last for 100 years or longer. Film archivists know that because many works from the earliest days of motion pictures, produced in the first decade of the 20th century or even before, are still around. Centuries from now, it'll be easy enough to retrieve whats stored on such films-a process that requires little more than a light source and a lens- even if information about how exactly those movies were made is lost.